Stand Oil is Polymerized Oil

In Reply to: Re: Oil of Delft posted by James Morton on 09/01/00 at 11:59 AM:

In my books, yes I can find that Stand Oil is not polymerized according to a definition by J. G. Bearn, "The Chemistry of Paints, Pigments and Varnishes 1923 - That it got it's name "Standole" from a German word, which in fact describes a drying oil, on standing, will separate out a coagulated mucilage. Simple.

Today artists regard the term "Stand Oil" as a poor descriptive but accepted term for polymerized oil. Heating drying oils and excluding oxygen, 250 degrees to 300 C and up, will undergo this change. As the heat rises the iodine number falls and the oil becomes thicker. No oxidation of the oil occurs as in Sun Thickened Oil. The chemical structure of Stand oil is identical to regular oil (some mass loss can occur when the oil is highly heated to a very thick consistancy). The only big change is the linking of molecules which will happen any way in any drying oil (linoxyn) but stand oil has the advantage that this thickening (colloidal polymerides) took place without the harmfull effects of oxygen.

Hope this clears things up :-)
John
 
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